Unlike in Britain, where public institutions routinely collect information about people’s ethnic origins, it is illegal in France to classify people in this fashion. The foundation stone of the secular French republic is that all citizens should be equal and free from distinctions of race or religion. But senior politicians have begun to recognise that France remains deeply disfigured by racism. To combat this, Sarkozy argues, it is necessary to collect ethnically based data. The British experience suggests that such policies often do more harm than good.

Two assumptions underlie the argument for ethnic monitoring: first, that ethnicity and culture are the most important labels we can place on people; and second, that there is a causal relationship between membership of such a group and disproportional outcomes between groups. …

Take, for instance, the question of educational attainment in Britain. We all know that Asians excel at school and that African Caribbeans perform worst. Except that they don’t. Pupils of Indian origin tend to do well, but the performance of Bangladeshis and Pakistanis is similar to that of African Caribbeans. Bottom of the class come white working-class boys.

Children of Bangladeshi and Pakistani origin used to be labelled “Asian”. Now they are more likely to be seen as “Muslim”. When they were Asians they were bracketed together with children of Indian origin, and the differences between the groups were largely ignored. Now that they are Muslims, the poor performance of Bangladeshis and Pakistanis has attracted attention, but is often put down to “Islamophobia”.